TABLE 2

pEC50 values of agonists, pIC50 values of antagonists (against the response to 10 μM 5-HT), and 5-HT maximum peak responses for calcium influx in the aequorin assay of HEK293 cells transiently expressing either homopentameric 5-HT3A receptors or heteromeric receptors of 5-HT3A with one of the novel subunits

Antagonist experiments and 5-HT maximum responses were performed in two separate groups.




5-HT3A

5-HT3A/C

5-HT3A/E

5-HT3A/Ea

5-HT3A

5-HT3A/D
Agonist pEC50 [(mean EC50) μM]
5-HT 5.75 ± 0.03 (1.81) 5.75 ± 0.04 (1.79) 5.78 ± 0.03 (1.66) 5.76 ± 0.03 (1.76) 5.70 ± 0.03 (2.02)
mCPBG 5.82 ± 0.03 (1.52) 5.80 ± 0.03 (1.61) 5.86 ± 0.04 (1.40) 5.74 ± 0.04 (1.83) 5.72 ± 0.03 (1.94)
Antagonist pIC50 [(mean IC50) nM]
Ondansetron 9.23 ± 0.06 (0.63) 9.34 ± 0.15 (0.52) 9.22 ± 0.07 (0.63) 9.35 ± 0.06 (0.46) 9.00 ± 0.02 (1.01) 8.88 ± 0.04 (1.33)
Azasetron 9.12 ± 0.01 (0.77) 9.09 ± 0.03 (0.83) 9.05 ± 0.04 (0.91) 9.15 ± 0.07 (0.74) 8.96 ± 0.03 (1.11) 8.87 ± 0.06 (1.39)
Emax [% of 5-HT3A + ss Emax]
100.00 ± 15.20
70.72 ± 10.61*
144.32 ± 22.82**
43.87 ± 5.59**
100.00 ± 6.95
145.76 ± 10.22**
  • Significant differences (repeated ANOVA followed by Dunnett's post test) compared with homopentameric 5-HT3A receptors: *p < 0.05, and **p < 0.01.